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Discussion Starter · #1 ·
I’m thinking about getting some headers for my 2002 IS but i don’t know anything about o2 sims or how the sensors even work, if i were to install the headers without a sim will the car even turn on? Or will it turn on but my mpg will go down a lot and i’ll get a CEL light, any help would be appreciated the sensors are the only thing holding me back right now from getting headers.
 

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The headers will come with provisions for all 4 o2 sensors. The upstream sensors (the upper two for both banks) can be screwed straight into the headers. These are what provide quick short term fuel trim changes to the ECU. These matter the most as they do the majority of fuel changes.

the downstream o2 sensors (the lower two for both banks) are what need o2 spacers/cel eliminators/simulators (aka whatever people want to call them) these can be purchased on Amazon for about $9-$20 each. You need 2 of them for the down stream sensors. Simply screw the spacer directly in the header, then screw the o2 sensors into the spacer.

While not 100% necessary, these spacers will try to keep the CEL from coming on. If you don’t run spacers, you WILL get a CEL but the car will run without issues.
 

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Discussion Starter · #5 ·
The headers will come with provisions for all 4 o2 sensors. The upstream sensors (the upper two for both banks) can be screwed straight into the headers. These are what provide quick short term fuel trim changes to the ECU. These matter the most as they do the majority of fuel changes.

the downstream o2 sensors (the lower two for both banks) are what need o2 spacers/cel eliminators/simulators (aka whatever people want to call them) these can be purchased on Amazon for about $9-$20 each. You need 2 of them for the down stream sensors. Simply screw the spacer directly in the header, then screw the o2 sensors into the spacer.

While not 100% necessary, these spacers will try to keep the CEL from coming on. If you don’t run spacers, you WILL get a CEL but the car will run without issues.
so basically all i have to worry about is the CEL light? no fuel economy or other malfunctions?
 

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some random brand my friend i selling they aren’t straight ebay garbage but definitely aren’t the most high end
I only ask because I fell victim to my own buying habits and went straight ebay garbage and have just stuck with it ever since. Long story short when it comes to O2 senser locations, only 3/4 have proper O2 bung placement, B2S1 cyl 4-6 upstream, is not able to fit. This will require you to re-weld a new O2 bung if it is the case

So just be careful because it could affect you depending on how far it is from pure china trash.


The other thing about new headers is that the mating flange. The stock headers to stock Y-pipe have indentations on each end that allow for enough room for the donut style compression gasket. If the headers you are buying do not have the indentation, like the shitty china ones I bought off ebay, you will see they have a flat face with no indentation. This causes the donut gaskets to become useless
 

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Discussion Starter · #10 ·
I only ask because I fell victim to my own buying habits and went straight ebay garbage and have just stuck with it ever since. Long story short when it comes to O2 senser locations, only 3/4 have proper O2 bung placement, B2S1 cyl 4-6 upstream, is not able to fit. This will require you to re-weld a new O2 bung if it is the case

So just be careful because it could affect you depending on how far it is from pure china trash.


The other thing about new headers is that the mating flange. The stock headers to stock Y-pipe have indentations on each end that allow for enough room for the donut style compression gasket. If the headers you are buying do not have the indentation, like the shitty china ones I bought off ebay, you will see they have a flat face with no indentation. This causes the donut gaskets to become useless
i’ve fell victim too ebay headers before too when i went to put them on they didn’t even line up with the studs on the engine, my friend has used these headers tho and says they are pretty good everything fits just need new gaskets. Thanks for the heads up tho
 

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Discussion Starter · #11 ·
I suppose a question to ask is.... why are you buying these? lol
So what ur saying is if u don’t know how something works on a car instead of asking questions or trying to learn about it just stay away from it? Good advice bud
 

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That is funny people. Everyone is saying they had trouble with Ebay headers. They all come from the same manufacturer. Just new logo on the box. Unless you buy a PPE or HKS ETC.. You get the same stuff. Even OBX does not make them. The issues with studs is very common on headers. A little prying and bingo. The O2 issue is because they where made for another body and just fit this one also. So tthey are not going to redo the wheel so to speak.
 

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i’ve fell victim too ebay headers before too when i went to put them on they didn’t even line up with the studs on the engine, my friend has used these headers tho and says they are pretty good everything fits just need new gaskets. Thanks for the heads up tho
Haha, I can't believe I forgot about that. I spent like an hour or two straight drilling steel because the holes on the ebay ones are so off from the studs.

So what ur saying is if u don’t know how something works on a car instead of asking questions or trying to learn about it just stay away from it? Good advice bud
I wouldn't mind that question from tobias, he's pretty chill about mostly everything I've ever run into him about. You're welcome from my end to learn as much as you want.

Since you're new, do you have a copy of most of the repair documents for our car? If you don't I can forward you to them

That is funny people. Everyone is saying they had trouble with Ebay headers. They all come from the same manufacturer. Just new logo on the box. Unless you buy a PPE or HKS ETC.. You get the same stuff. Even OBX does not make them. The issues with studs is very common on headers. A little prying and bingo. The O2 issue is because they where made for another body and just fit this one also. So tthey are not going to redo the wheel so to speak.
Ya, i'm not quite sure how many people don't know that, I sure do, and that's why I was searching for the cheapest ones on the market at the time. At only $89, it's not too bad, provided I don't run into an exhaust leak every 4-6 months :rolleyes:

It's just difficult spending as much as $1,300 on a set of headers when the cheaper ones are also on the internet.

As for the O2 placement, I actually don't have an engine code despite the sensor just chilling the engine bay, weird but it's never been a huge deal.
 

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Discussion Starter · #14 ·
Haha, I can't believe I forgot about that. I spent like an hour or two straight drilling steel because the holes on the ebay ones are so off from the studs.



I wouldn't mind that question from tobias, he's pretty chill about mostly everything I've ever run into him about. You're welcome from my end to learn as much as you want.

Since you're new, do you have a copy of most of the repair documents for our car? If you don't I can forward you to them



Ya, i'm not quite sure how many people don't know that, I sure do, and that's why I was searching for the cheapest ones on the market at the time. At only $89, it's not too bad, provided I don't run into an exhaust leak every 4-6 months :rolleyes:

It's just difficult spending as much as $1,300 on a set of headers when the cheaper ones are also on the internet.

As for the O2 placement, I actually don't have an engine code despite the sensor just chilling the engine bay, weird but it's never been a huge deal.
i’m not quite sure what u mean by the repair document are you talking about the owners manual?
 

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i’m not quite sure what u mean by the repair document are you talking about the owners manual?
No, there is an entire set of repair documentation that mechanics and technicians use for diagnosis.

There are 2 main documents, the Wiring section, and the Repair manual. I have another one in the collections called the "tech manual", but I don't quite know if there is any differences between it and the repair manual

Anyhow, grab a copy for yourself, it can save you a lot of money

 

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So what ur saying is if u don’t know how something works on a car instead of asking questions or trying to learn about it just stay away from it? Good advice bud
Excuse me? I asked why are you buying questionable headers from your friend. How on earth did you put those words in my mouth?

Let me rephrase. What is wrong with the stock headers? What is your goal here? We're trying to help.
 

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Discussion Starter · #17 ·
Excuse me? I asked why are you buying questionable headers from your friend. How on earth did you put those words in my mouth?

Let me rephrase. What is wrong with the stock headers? What is your goal here? We're trying to help.
my bad bro i thought u were trolling didn’t mean to be rude. i’m just trynna make my shit louder
 

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Discussion Starter · #18 ·
No, there is an entire set of repair documentation that mechanics and technicians use for diagnosis.

There are 2 main documents, the Wiring section, and the Repair manual. I have another one in the collections called the "tech manual", but I don't quite know if there is any differences between it and the repair manual

Anyhow, grab a copy for yourself, it can save you a lot of money

thanks bro
 

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my bad bro i thought u were trolling didn’t mean to be rude. i’m just trynna make my shit louder
Just know if you make it annoyingly loud it will increase your driving fatigue. Sounds stupid, but if you drive long distances it can really start to get at you subconsciously.

Catless headers don't really do much to make the car louder if the remainder of the system, y-pipe, resonator, and axle-back are all stock or stock replacements. I would only recommend doing a straight pipe all the way back if it's a track or drift car.
 

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Discussion Starter · #20 ·
Just know if you make it annoyingly loud it will increase your driving fatigue. Sounds stupid, but if you drive long distances it can really start to get at you subconsciously.

Catless headers don't really do much to make the car louder if the remainder of the system, y-pipe, resonator, and axle-back are all stock or stock replacements. I would only recommend doing a straight pipe all the way back if it's a track or drift car.
as far as exhaust right now i have an hks catback, resonator delete, and all stock cats. u think it’ll do much getting catless headers if i’ll still have the hks cat back and mid pipe cat?
 
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